PEIRS: a pathologist-maintained expert system for the interpretation of chemical pathology reports.

Provision of a comprehensive interpretative service is an important challenge facing chemical pathologists. Attempts to automate report interpretation using expert systems have been limited in the past by the difficulties of rule base maintenance. We have applied a novel knowledge acquisition technique, ripple down rules, in the development of PEIRS (Pathology Expert Interpretative Reporting System), a user-maintained expert system for automating chemical pathology report interpretation. We created over 950 rules for thyroid function tests, arterial blood gases and other test sub-groups in 9 mths of operation. A staff pathologist performed all maintenance tasks as part of his routine duties without any need for computer programming skills. No clerical staff involvement was required. Duplication of rule addition for reports requiring multiple comments was the only limitation to coverage of other high volume test groups. PEIRS is the first expert system for the automated interpretation of a range of chemical pathology reports which operates in routine use without extra staffing requirements. PEIRS does not require "knowledge engineering" expertise. Thus, the knowledge base is flexible and can be easily maintained and updated by the pathologist. Expert systems based on ripple down rules should enable pathologists to provide a comprehensive automated interpretative service within the context of the total testing process.